package org.bpms.util;

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.security.MessageDigest;
import java.util.Random;
import javax.imageio.ImageIO;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.Cookie;
import com.jfinal.core.Controller;
import com.jfinal.render.Render;

/**
 * 图片验证码生成工具
 * @author hupei
 *
 */
public class CaptchaRender extends Render {
	private static final long serialVersionUID = -7599510915228560611L;

	private static final String[] strArr = { "3", "4", "5", "6", "7", "8", "9", "A", "B", "C", "D", "E", "F", "G", "H",
			"J", "K", "M", "N", "P", "Q", "R", "S", "T", "U", "V", "W", "X", "Y" };

	private static String randomCodeKey = "JFINAL_JLHHWH_Key";
	private static boolean caseInsensitive = true;

	private int img_width = 85;
	private int img_height = 20;
	private int img_randNumber = 6;

	public CaptchaRender() {
	}

	public CaptchaRender(String randomKey) {
		if (null == randomKey || randomKey.equals(""))
			throw new IllegalArgumentException("randomKey can not be blank");
		randomCodeKey = randomKey;
	}

	public CaptchaRender(int width, int height, int count, boolean isCaseInsensitive) {
		if (width <= 0 || height <= 0 || count <= 0) {
			throw new IllegalArgumentException("Image width or height or count must be > 0");
		}
		this.img_width = width;
		this.img_height = height;
		this.img_randNumber = count;
		caseInsensitive = isCaseInsensitive;
	}

	public CaptchaRender(String randomKey, int width, int height, int count, boolean isCaseInsensitive) {
		if (null == randomKey || randomKey.equals(""))
			throw new IllegalArgumentException("randomKey can not be blank");
		randomCodeKey = randomKey;

		if (width <= 0 || height <= 0 || count <= 0) {
			throw new IllegalArgumentException("Image width or height or count must be > 0");
		}
		this.img_width = width;
		this.img_height = height;
		this.img_randNumber = count;
		caseInsensitive = isCaseInsensitive;
	}

	public void render() {
		BufferedImage image = new BufferedImage(img_width, img_height, BufferedImage.TYPE_INT_RGB);
		String vCode = drawGraphic(image);
		vCode = encrypt(vCode);
		Cookie cookie = new Cookie(randomCodeKey, vCode);
		cookie.setMaxAge(-1);
		cookie.setPath("/");
		response.addCookie(cookie);
		response.setHeader("Pragma", "no-cache");
		response.setHeader("Cache-Control", "no-cache");
		response.setDateHeader("Expires", 0);
		response.setContentType("image/jpeg");

		ServletOutputStream sos = null;
		try {
			sos = response.getOutputStream();
			ImageIO.write(image, "jpeg", sos);
		} catch (Exception e) {
			throw new RuntimeException(e);
		} finally {
			if (sos != null)
				try {
					sos.close();
				} catch (IOException e) {
					e.printStackTrace();
				}
		}
	}

	private String drawGraphic(BufferedImage image) {
		// 获取图形上下文
		Graphics g = image.createGraphics();
		// 生成随机类
		Random random = new Random();
		// 设定背景色
		g.setColor(getRandColor(200, 250));
		g.fillRect(0, 0, img_width, img_height);
		// 设定字体
		g.setFont(new Font("Times New Roman", Font.PLAIN, 38));

		// 随机产生155条干扰线，使图象中的认证码不易被其它程序探测到
		g.setColor(getRandColor(160, 200));
		for (int i = 0; i < 155; i++) {
			int x = random.nextInt(img_width);
			int y = random.nextInt(img_height);
			int xl = random.nextInt(12);
			int yl = random.nextInt(12);
			g.drawLine(x, y, x + xl, y + yl);
		}

		// 取随机产生的认证码(img_randNumber位数字)
		String sRand = "";
		for (int i = 0; i < img_randNumber; i++) {
			String rand = String.valueOf(strArr[random.nextInt(strArr.length)]);
			sRand += rand;
			// 将认证码显示到图象中
			g.setColor(new Color(20 + random.nextInt(110), 20 + random.nextInt(110), 20 + random.nextInt(110)));
			// 调用函数出来的颜色相同，可能是因为种子太接近，所以只能直接生成
			g.drawString(rand, 23 * i + 17, 33);
		}

		// 图象生效
		g.dispose();

		return sRand;
	}

	/*
	 * 给定范围获得随机颜色
	 */
	private Color getRandColor(int fc, int bc) {
		Random random = new Random();
		if (fc > 255)
			fc = 255;
		if (bc > 255)
			bc = 255;
		int r = fc + random.nextInt(bc - fc);
		int g = fc + random.nextInt(bc - fc);
		int b = fc + random.nextInt(bc - fc);
		return new Color(r, g, b);
	}

	private static final String encrypt(String srcStr) {
		try {
			String result = "";
			MessageDigest md = MessageDigest.getInstance("MD5");
			byte[] bytes = md.digest(srcStr.getBytes("utf-8"));
			for (byte b : bytes) {
				String hex = Integer.toHexString(b & 0xFF).toUpperCase();
				result += ((hex.length() == 1) ? "0" : "") + hex;
			}
			return result;
		} catch (Exception e) {
			throw new RuntimeException(e);
		}
	}

	public static boolean validate(Controller controller, String inputRandomCode) {
		if (null == inputRandomCode || inputRandomCode.equals(""))
			return false;
		try {
			if (caseInsensitive)
			inputRandomCode = inputRandomCode.toUpperCase();
			inputRandomCode = encrypt(inputRandomCode);
			return inputRandomCode.equals(controller.getCookie(randomCodeKey));
		} catch (Exception e) {
			e.printStackTrace();
			return false;
		}
	}
}
